DETROIT, MI — It sounds like an action-packed scene from a Hollywood movie, but in reality, it's just another day in Detroit.

While fueling her vehicle at a BP gas station on Jefferson, a woman had her vehicle stolen by an armed carjacker about 8 a.m. Thursday. As he fled, a good Samaritan who witnessed the theft jumped in his car and gave chase, said Detroit Public Information Officer Adam Madera.

Madera said the suspect fled toward the Detroit River and blasted through a barrier of a waterfront dock three to four blocks away. Before plummeting into the waterway, the suspect dove from the vehicle and took refuge in some nearby brush.

The chasing witness exited his vehicle to check if the suspect still occupied the mostly submerged vehicle; and a shootout ensued. Madera said he doesn't know who fired first.

The good Samaritan suffered a nonfatal gunshot wound and is hospitalized in temporarily serious condition.

The opportunistic carjacker swapped his newly acquired drowning SUV for the victim's 2009 Ford focus and again fled.

He is still wanted by police.

The suspect, wearing a blue, hooded sweatshirt, dark pants, described as a black man in his 30s with a goatee, escaped and it's unknown if he suffered a gunshot wound during the exchange of gunfire, said Madera.